The control of column temperature is important to the resolving efficiency of a liquid-chromatography (LC) column regardless of whether the system is designed to operate isothermally or by temperature programmed analysis. Column temperature control is commonly achieved by heating of the column, for example, in a convection oven or in an oven with still air.
Some chromatographic systems utilize a column heater to control column temperature. For example, the column may be located in a temperature controlled chamber. The temperature of the fluid mixture or mobile phase provided to the column may not be constant, especially for long (e.g., multi-hour) chromatographic runs where the variations in room temperature are significant. Temperature variations can adversely impact the accuracy of the chromatographic analysis. In some systems, a device is used to pre-heat the mobile phase before the mobile phase is injected into the column to reduce column inlet fluid temperature fluctuations.
The design of the column oven is typically different for different chromatographic systems. The particular design used is based, in part, on the requirement to achieve stable retention times and separation metrics (e.g., selectivity, peak shape and column efficiency) despite variations in the ambient temperature; however, variances in the designs can lead to differences in chromatographic results when separations of identical samples are performed on different LC systems.